Therapeutic Efficacy of a Very Low/Low Dose of Lenvatinib in Advanced Radioiodine-Refractory Thyroid Cancer: A Real-World Series from a Single Center

Background: Lenvatinib is a receptor tyrosine kinase inhibitor indicated for advanced radioiodine-refractory thyroid cancer (RAI-RTC). It is recommended to start at 24 mg per day; however, in patients who are at risk of severe adverse events, it may be reasonable to start at lower doses. Patients and Methods: We included 15 patients with RAI-RTC who started lenvatinib at a very low/low dose and evaluated the efficacy and safety. Results: Eight patients (53.3%) did not show progression of the disease, and about half of the patients (53.3%) were alive at the last follow-up visit. Up to 26.6% of patients achieved a partial response to therapy, with a notable volume reduction in the local and metastatic lesions. However, 80% of patients experienced adverse events, mainly of a moderate grade. Conclusions: Although these findings are based on a small sample size and a single-center study, treatment with lenvatinib at very low/low doses in fragile patients seems to be a promising strategy for the management of RAI-RTC, balancing effective disease control with a favorable safety profile.